CUTTING AND WELDING DEVICE FOR A WRAPPING MACHINE
[0001] As its name indicates, the invention is an electric modular cutting and welding device
of reduced size, suitable for being located between the blades of an electric mobile
pallet truck. The system complements wrapping machines that comprise a shaft from
which a mobile arm hangs with a film spool holder carriage and wherein the spool holder
carriage orbits around wrapping the load in film such that, in an automated fashion,
it performs the film fastening operations at the start of the wrapping cycle, welding
the film and cutting it at the end of the wrapping cycle.
[0002] It belongs to the art sector of wrapping machines.
BACKGROUND
[0003] Wrapping machines generally have a first film fastening process which enables the
start of the wrapping, and once the wrapping process completes, the film is then welded
and cut.
[0004] In general, the film is held on a spool that wraps the pallet perimeter, whether
the spool moves upwardly and downwardly only and the pallet rotates, or the pallet
remains in a fixed position, and the film spool rotates around it, wrapping it.
[0005] There is a large variety of wrapping machines, some of which are present on production
lines and are fixed, and others are externally located outside the production line
and can even be transportable.
[0006] Normally most fixing, welding, and film cutting processes are done manually, and
this implies a disadvantage associated with the times in its execution since, for
each start and end of the wrapping process, an operator is required to carry out the
tasks of starting, attachment of the film to the pallet and end of the cycle.
[0007] Patent
ES2341209, owned by the applicant itself, refers to a wrapping machine with a lower rotary
arm with a spool holder carriage that generates a tension suitable for wrapping. This
solution, however, requires a manual operation for the start and end of the wrapping
cycle leading to additional time expenditure.
[0008] To solve this problem, known solutions exist that require pneumatic installations,
which need a pre-installation where the wrapping machine will go.
[0009] One example of this type of execution is patent
ES2090944 which relates to a unit for thermo-sealing a plastic film used in machines to wrap
stacks of articles to palletize them. These types of solutions require complex installations
of considerable size.
[0010] As patent
US4619102, which relates to a system for thermo-sealing a wrapping film that holds the cut
end in position in such a way that enables the subsequent operation of wrapping a
pallet, this system, just like the previous one, requires a pneumatic system to activate
the device's pistons and cylinders.
[0011] The process of fastening the film, welding, and subsequent cut in most wrapping machines
is performed manually except for patent
EP13791009.7 owned by the applicant
ES1077170U, which relates to the automated process of cutting and welding suitable for coupling
to semi-automatic wrapping machines, also called external, this invention eliminates
any requirement of external dependency except electrical power.
[0012] However, this device requires a space that, despite not being a problem in conventional
wrapping machines, prevents the use thereof in portable wrapping machines of the kind
associated with a pallet truck, given that the only space available is in between
the blades thereof.
DESCRIPTION OF THE INVENTION
[0013] In order to overcome the problems set out, the invention refers to a cutting and
welding device suitable for being situated between the blades of an electric mobile
pallet truck, preferably in the closest section to the main body thereof.
[0014] The device is designed for use in wrapping machines that comprise a shaft from which
a mobile arm hands with a film spool holder carriage and wherein the spool holder
carriage orbits around wrapping the load in the film while the load remains static.
[0015] The device presents a work zone and a rest zone, separated by a central zone or a
transit zone.
[0016] The work zone of the device, located furthest away from the main body of the pallet
truck, comprises:
- A film fastening gripper;
- A contrast plate that collaborates with the cutting and welding operations;
- Moreover, at the time of performing the cutting and welding operations, a welding
carriage moves to this work zone.
[0017] The rest zone, contiguous to the main body of the pallet truck in the direction in
which the blades are projected, comprises:
- The welding carriage when it is not performing cutting and welding operations;
- Drive motor of the contrast plate;
- A linear electric actuator.
[0018] Between the rest zone and the work zone, there is a central zone or transit zone
sufficiently extensive and free of obstacles to enable the passage of the spool holder
carriage in the wrapping operations.
[0019] The welding carriage moves from the rest zone to the work zone, and inversely, preferably
supported by a guide that crosses the transit zone and is driven by a linear electric
actuator.
[0020] The contrast plate and the gripper are in the work zone and retract while not in
use in a fixed location between the pallet truck blades at the height of the physical
limit of the pallet.
[0021] Except for the cutting and welding carriage, the rest of the elements remain, during
rest, below the upper level of the pallet truck blades, enabling them to be covered
with protective planks without over-raising the height de the blades or interfering
with the maneuvers of the spool holder carriage.
[0022] This protection leaves one free track, which enables the path of the welding carriage.
[0023] The wrapping cycle begins by wrapping the palletized load arranged on the blades
of the pallet truck.
[0024] For this, the gripper is in raised position holding the film from the end of the
previous cycle. The spool of the film starts to turn around the load to be wrapped,
and in these first turns the contrast plate, which is in a raised position, stays
between the load and the film, and remains like this until the wrapping cycle ends.
[0025] Apart from the movement around the load, the film spool performs an upward and downward
movement, encompassing the entire height and volume of the load to be wrapped.
[0026] During this process, the cutting and welding carriage are set in the rest zone.
[0027] Once the wrapping finishes, the cutting and welding carriage moves from the rest
zone to the work zone and presses with heat against the contrast plate, thus welding
the different layers of film and cutting the film at a point between the weld and
the spool, leaving the loose film end trapped by the gripper.
[0028] At this point, the cutting and welding carriage returns to the rest zone, and the
contrast plate is retracted and remains housed in the gap between the pallet truck
blades, thus ending the wrapping cycle, allowing the pallet with the load already
wrapped to be freely handled and to load another pallet onto the pallet truck for
the start of a new cycle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029]
FIGURE 1 shows a perspective view, where it is possible to see the device (1) which
comprises the welding and cutting carriage (7) at rest, the drive motor (8) of the
contrast plate, the contrast plate (6), and the retracted gripper (5).
FIGURE 2 shows a side view, the arrangement and location of the work zone (2) showing
the retracted gripper (5). Also shown is the rest zone (3) that comprises the welding
and cutting carriage (7) and the transit zone (4) from which the cable-carrying chain
(13) can be seen and which connects both zones.
FIGURE 3 shows a top view where it is possible to see the guide (10), which enables
the displacement of the welding and cutting carriage (7) from the work zone to the
rest zone and vice versa, the linear electric actuator (9) and the cable-carrying
chain (13) that enable the cables of the device to be guided throughout the entire
route. The contrast plate in the rest position is also shown.
FIGURE 4 presents a view of the device with the protective planks (12) that safeguard
the elements of the device without exceeding the height limit of the pallet, showing
the guide (10), the drive motor (8), the cutting and welding carriage (7) and the
contrast plate (6).
FIGURE 5 shows a perspective view of the device combination between the pallet truck
blades (11), and with a pallet inserted, and the location of the system elements,
the welding and cutting carriage (7) and the gripper (6) are displayed clearly. The
main body (14) of the pallet truck is also shown.
[0030] The shaft, arm and spool holder carriage of the wrapping machine have not been included
in any drawing to avoid elements that might distract away from the invention claimed.
DESCRIPTION OF A WAY OF CARRYING OUT THE INVENTION
[0031] The present invention is neither unique nor limiting, but merely expository of the
object to be protected hereby.
[0032] The cutting and welding system consists of a device (1) that has a work zone (2)
and a rest zone (3) separated by a transit zone (4) such that the work zone (2) comprises:
- A gripper (5);
- A contrast plate (6);
- And in cutting and welding operations, a cutting and welding carriage (7).
[0033] The rest zone (3) located contiguous to the main body of the pallet truck comprises:
- At rest a cutting and welding carriage (7), wherein this cutting and welding carriage
moves to the work zone during the cutting and welding operations;
- Drive motor (8) of the contrast plate;
- Linear electric actuator (9);
[0034] The transit zone (4) has a larger space than the spool holder carriage such that
it is sufficient to enable the passage of the spool holder carriage in the wrapping
operations.
[0035] The cutting and welding carriage (7) is driven by the linear electric actuator (9)
that moves it from the rest zone to the work zone and back again through the transit
zone (4) by way of a guide (10).
[0036] Both the gripper (5) and the contrast plate (6) are located at a fixed location between
the pallet truck blades (11) and retract while they are not in use.
[0037] Some protective planks (12), that cover the elements that comprise the device, with
the exception of the welding carriage (7), and the guide (10) thereof which enables
its displacement from the rest zone (3) to the work zone (2) and vice versa.
[0038] To begin a wrapping cycle, the gripper (5), in a raised position, holds the film;
the spool of the film (not shown) begins to turn around the load to be wrapped, the
drive motor (8) of the contrast plate activates the contrast plate (6) remaining in
raised position between the pallet load and the film, maintaining this position until
the wrapping cycle ends.
[0039] Once the wrapping action finishes, the cutting and welding carriage (7) moves from
the rest zone (3) to the work zone (2) driven by the linear electric actuator (9)
said carriage presses against the contrast plate (6) applying heat and thus welding
the layers of film, to then cut the film at a point between the weld and the gripper,
the remaining loose film is held by the gripper (5).
[0040] Once the welding and cutting has ended, the welding and cutting carriage (7) moves
again to the rest zone (3) and the contrast plate (6) is retracted to a horizontal
position by the drive motor (8) housed in the space between the blades of the pallet
truck (11) for the start of a new wrapping cycle.
1. A CUTTING AND WELDING DEVICE FOR A WRAPPING MACHINE, wherein the wrapping machine
comprises a pallet truck, with a shaft joined to its main body, and from this shaft
a mobile arm hangs with a film spool holder carriage and wherein the spool holder
carriage orbits around to wrap a load in film,
characterized in that the cutting and welding device is located between the pallet truck blades (11) and
comprises a work zone (2) and a rest zone (3), both being separated by a transit zone
(4).
Wherein the work zone of the device, set in its position furthest away from the main
body (14) of the pallet truck, comprises:
• A film fastening gripper (5)
• A contrast plate (6) that collaborates in the cutting and welding operations
• Moreover, at the time of performing the cutting and welding operations, a welding
carriage (7) moves to this work zone.
The rest zone (3), contiguous to the main body of the pallet truck on the side on
which the blades are projected, comprises:
• The welding carriage (7), when no cutting and welding operations are being performed.
The transit zone (4) that connects the rest zone (3) and the work zone (2).
Where the welding and cutting carriage (7) crossing the transit zone (4), moves from
the rest zone (3) towards the work zone (2) where it performs the cutting and welding
operations, and then returns to the rest zone (3). The transit zone (4) is extensive
enough to enable the passage of the spool holder carriage in the wrapping operations.
2. THE CUTTING AND WELDING DEVICE IN A MOBILE ELECTRIC PALLET TRUCK according to claim
1, characterized by further comprising a linear electric actuator (9) that drives the welding and cutting
carriage (7).
3. THE CUTTING AND WELDING DEVICE IN A MOBILE ELECTRIC PALLET TRUCK according to claim
1, characterized in that the linear electric actuator (9) is located in the rest zone (3).
4. THE CUTTING AND WELDING DEVICE IN A MOBILE ELECTRIC PALLET TRUCK according to claim
1, characterized in that the welding and cutting carriage (7) moves towards the work zone (2) by means of
a guide (10) that crosses the transit zone.
5. THE CUTTING AND WELDING DEVICE IN A MOBILE ELECTRIC PALLET TRUCK according to claim
1, characterized by further comprising a drive motor (8) of the contrast plate (6).
6. THE CUTTING AND WELDING DEVICE IN A MOBILE ELECTRIC PALLET TRUCK according to claim
5, characterized in that the drive motor (8) is located in the rest zone (3).
7. THE CUTTING AND WELDING DEVICE IN A MOBILE ELECTRIC PALLET TRUCK according to claim
1, characterized in that the contrast plate (6) pivots from a horizontal to a vertical position and vice versa.